It has been found that it is necessary to mount a cargo payload in, for example, the cargo bay of a space shuttle in such a manner that the cargo is held substantially rigidly in the cargo bay, during launching and landing of the space shuttle. If the cargo in the cargo bay can dynamically couple or resonate with the structure of the space shuttle, the resulting dynamic loads may put the space shuttle off course, or produce structural damage to the cargo or the shuttle. The excitation forces come from, for example, the solid rocket boosters on launching, or the dynamic loads from the aerodynamics or contact with the ground on landing.
It has also been found that it is necessary to mount a cargo in, for example, the cargo bay of a space shuttle in such a manner that, once the space shuttle is in orbit around the Earth it is possible to gently release the cargo (e.g. a communications satellite) from the attachment in the cargo bay without using excessive force.
It goes without saying that such a cargo mounting would also be useful for transporting cargo by land, sea or air and for storage of such cargo on land or in space.
Yet another requirement that has been found is that the cargo must be mounted in such a manner as to be able to distort to accommodate thermal expansion of the structural materials due to the orbiting spacecraft cargo being subjected to temperature gradients.
There is a need for a cargo mounting which will hold the cargo substantially rigidly, which will allow the cargo to be released gently without use of excessive force, and which will allow the cargo to distort to accommodate thermal expansions due to temperature differentials across the cargo, and temperature differentials from the nominal design and manufacturing temperature, i.e. room temperature.
It has already been disclosed in, for example, U.S. Pat. No. 3,351,212, dated Nov. 7, 1967, "Pallet Rack Construction", K. McConnell, to provide one side of a pallet support beam with upper and lower, flattened hemispherical headed, studs for engaging keyhole slots in the uprights of a support frame forming a stirrup assembly for the studs. The heads of the studs are shaped as flattened hemispheres for guidance into the keyhole slots and to provide a flat underside support frame for the engaging surface. The keyhole slots in the uprights are to one side of the frame forming the stirrup assembly so that the studs will cantilever the pallet support beam from one side of the support frame.
While the support frame disclosed in the McConnell patent is useful it is not intended to, and is not capable of, securing the studs in such a manner that:
a) buffering the pallet support beam against vibrational loads is avoided,
b) the beam is secured from reverberation of the studs in the keyhole slots, and
c) any significant thermally induced distortions encountered will be accommodated.